Patent Application
20230122314
The present application is a National Stage Application of PCT International Application No. PCT/IB2021/052375 (filed on Mar. 23, 2021), under 35 U.S.C. §371, which claims priority to European Patent Application No. EP 20166569.2 (filed on Mar. 30, 2020), which are each hereby incorporated by reference in their complete respective entireties.
The present invention relates to the field of batteries, and more particularly to lithium-ion batteries. The invention relates to lithium-ion batteries with a novel architecture giving them a longer life. The invention further relates to a novel method for manufacturing such batteries.
Rechargeable all-solid-state lithium-ion batteries are known. International Patent Publication No. WO 2016/001584 (I-TEN) describes a lithium-ion battery made from anode foils comprising a conductive substrate covered successively with an anode layer and an electrolyte layer, and cathode foils comprising a conductive substrate covered successively with a cathode layer and an electrolyte layer; these foils are cut, before or after deposition, into U-shaped patterns. These foils are then stacked alternately in order to form a stack of a plurality of unit cells. The anode and cathode foil cutting patterns are placed in a “head-to-tail” configuration such that the stacking of the cathodes and of the anodes is laterally offset. After the stacking step, a thick-layer encapsulation system about ten microns thick is deposited on the stack and in the available cavities present within the stack. This firstly ensures the stiffness of the structure at the cutting planes and secondly protects the battery cell from the atmosphere. Once the stack has been produced and is encapsulated, it is cut along cutting planes to obtain unit batteries, with the cathode connection zones and anode connection zones of the batteries being exposed on each of the cutting planes. When these cuts are made, the encapsulation system can be torn off, resulting in a break in the battery's impervious seal. Terminations (i.e. electrical contacts) are also known to be added where these cathode and anode connection zones are apparent.
It has become apparent that this known solution can have certain drawbacks. More specifically, depending on the positioning of the electrodes, in particular the proximity of the edges of the electrodes for multi-layer batteries and the cleanness of the cuts, a leakage current can appear at the ends, typically in the form of a creeping short-circuit. This creeping short-circuit reduces battery performance, despite the use of an encapsulation system around the battery and near the cathode and anode connection zones. Moreover, an unsatisfactory deposition of the encapsulation system on the battery is occasionally observed, in particular on the edges of the battery at the spaces created by the lateral offsetting of the electrodes on the edges of the battery.
U.S. Patent Publication No. 2018/0212210 filed by Suzuki also discloses a battery firstly comprising a plurality of unit cells. The resulting stack is placed in a metal casing with the interposition of a resin. This secures the cells mechanically, so that they do not move during operation. This resin also prevents the risk of short-circuits, which would result from the cells coming into contact with the metal casing, in particular during potential impacts or vibrations.
Finally, Japanese Patent Publication No. JP 2007/005279 filed by Matsushita is cited. This document discloses an all-solid-state battery obtained by sintering. This battery thus comprises neither an electrolyte material nor a layer of a separator impregnated with such an electrolyte.
The present invention aims to overcome, at least in part, some of the aforementioned drawbacks of the prior art, and in particular to obtain rechargeable lithium-ion batteries with a high energy density and a high power density.
It in particular aims to increase the production output for rechargeable lithium-ion batteries with a high energy density and a high power density and to produce more efficient encapsulations at a lower cost.
It in particular aims to propose a method that reduces the risk of a creeping or accidental short-circuit, and that allows a battery with a low self-discharge rate to be manufactured.
It in particular aims to propose a method that allows a battery with a very long life to be manufactured in a simple, reliable and fast manner.
It further aims to propose a simple, fast and cost-effective method for manufacturing batteries.
The invention firstly relates to a battery comprising at least one unit cell, each unit cell successively comprising an anode current-collecting substrate, an anode layer, at least one layer of an electrolyte material and/or at least one layer of a separator impregnated with an electrolyte, a cathode layer, and a cathode current-collecting substrate, wherein, in the case where said battery comprises a plurality of unit cells, said unit cells are disposed one below the other, i.e. superimposed according to a frontal orientation relative to the main plane of the battery, such that, preferably:
wherein the first longitudinal face of the battery comprises at least one anode connection zone and that a second longitudinal face of the battery comprises at least one cathode connection zone, said anode and cathode connection zones being laterally opposite one another, wherein in a first longitudinal direction of the battery, each anode current-collecting substrate protrudes from each anode layer, from each layer of electrolyte material or layer of a separator impregnated with an electrolyte, from each cathode layer and from each cathode current-collecting substrate layer, and
wherein in a second longitudinal direction of the battery that is opposite to said first longitudinal direction, each cathode current-collecting substrate protrudes from each anode layer, from each layer of electrolyte material or layer of a separator impregnated with an electrolyte, from each cathode layer and from each anode current-collecting substrate layer.
In one specific embodiment:
According to a particularly advantageous embodiment of the invention, the battery according to the invention comprises an encapsulation system covering at least part of the outer periphery of the stack, said encapsulation system including at least one impervious cover layer, having a water vapour permeance (WVTR) of less than 10−5 g/m2.d, this encapsulation system being in direct contact at least with said layer of electrolyte material and/or with said layer of a separator impregnated with an electrolyte, at each longitudinal face. Preferably, the encapsulation system is also in direct contact, at each longitudinal face, with the anode layer, the cathode layer and the non-protruding current-collecting substrate.
Advantageously, the encapsulation system is electrically insulating, the conductivity of this encapsulation system advantageously being less than 10e-11 S.m−1, in particular less than 10e-12 S.m−1.
Advantageously, the encapsulation system covers at least part of the outer periphery of the stack, said encapsulation system covering the end faces of the stack, the lateral faces and at least part of the longitudinal faces, such that:
According to yet another aspect of the invention, the encapsulation system comprises:
wherein when said second cover layer is present: a succession of said second cover layer and of said third cover layer can be repeated z times, where z≥1, and deposited on the outer periphery of at least the third cover layer, and the last layer of the encapsulation system being an impervious cover layer, preferably having a water vapour permeance (WVTR) of less than 10-5 g/m2.d, and being made of a ceramic material and/or a low melting point glass.
According to yet another aspect of the invention, at least the anode connection zone, preferably the first longitudinal face comprising at least the anode connection zone, is covered by an anode contact member, and at least the cathode connection zone, preferably the second longitudinal face comprising at least the cathode connection zone, is covered by a cathode contact member, wherein said anode and cathode contact members are capable of producing the electrical contact between the stack and an external conductive element.
According to yet another aspect of the invention, each of the anode and cathode contact members comprises:
According to yet another aspect of the invention, the smallest distance between the first longitudinal face comprising at least one anode connection zone and the first end plane defined by the first longitudinal ends of each anode layer, of each layer of electrolyte material and/or separator layer, of each cathode layer and of each cathode current-collecting substrate layer is comprised between 0.01 mm and 0.5 mm, and/or the smallest distance between the second longitudinal face comprising at least one cathode connection zone and the second end plane defined by the second longitudinal ends of each anode layer, of each layer of electrolyte material and/or separator layer, of each cathode layer and of each anode current-collecting substrate layer, is comprised between 0.01 mm and 0.5 mm.
The invention further relates to a method for manufacturing at least one battery, each battery comprising at least one unit cell, each unit cell successively comprises an anode current-collecting substrate, an anode layer, at least one layer of an electrolyte material and/or at least one layer of a separator impregnated with an electrolyte, a cathode layer, and a cathode current-collecting substrate, wherein, in the case where said battery comprises a plurality of unit cells, said unit cells are disposed one below the other, i.e. superimposed according to a frontal orientation relative to the main plane of the battery, wherein:
wherein the first longitudinal face of the battery comprises at least one anode connection zone and that a second longitudinal face of the battery comprises at least one cathode connection zone, said anode and cathode connection zones being laterally opposite one another, such that:
The manufacturing method comprises:
In one specific embodiment of the method, after the sixth step (if carried out), or if the sixth step is not carried out, after the fifth step (if carried out), or if the sixth step and the fifth step are not carried out, after the fourth step, and before the seventh step, an eighth step of encapsulating the consolidated stack or battery line is carried out, preferably in which, at least part of the outer periphery of the stack or of the battery line, preferably the end faces of the stack or of the battery line, the lateral faces and at least part of the longitudinal faces, are covered by an encapsulation system such that:
The encapsulation system preferably comprises:
wherein a sequence of at least one second cover layer and at least one third cover layer can be repeated z times, where z≥1, and deposited at the outer periphery of at least the third cover layer, and that the last layer of the encapsulation system is an impervious cover layer, preferably having a water vapour permeance (WVTR) of less than 10−5 g/m2.d, and being made of a ceramic material and/or a low melting point glass.
In another specific embodiment of the method according to the invention, which can be combined with the above, after the seventh step, at least the anode connection zone, preferably at least the first longitudinal face comprising at least the anode connection zone, is covered by an anode contact member, capable of producing the electrical contact between the stack and an external conductive element, and at least the cathode connection zone, preferably at least the second longitudinal face comprising at least the cathode connection zone, is covered by a cathode contact member, capable of producing the electrical contact between the stack and an external conductive element, said production of anode and cathode contact members comprising:
The accompanying figures, given as non-limiting examples, show different aspects and embodiments of the invention.
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As a rule, the following geometric designations are associated with this battery:
ZZ refers to the so-called frontal orientation, i.e. perpendicular to the plane of the different stacked layers;
XX refers to the so-called longitudinal orientation, which is included in the plane of the stacked layers and which is parallel to the largest dimension of these layers, when viewed from above, i.e. in the frontal orientation;
YY refers to the so-called lateral or transverse orientation, which is included in the plane of the stacked layers and which is parallel to the smallest dimension of these layers, when viewed from above.
Also as a rule, the two directions associated with each of these three orientations are given with reference to the plane of the foil on which
The rightwards and leftwards directions are thus associated with the XX orientation, the forwards and backwards directions are associated with the YY orientation, and the upwards and downwards directions are associated with the ZZ orientation, with reference to the plane of the foil on which
Also as a rule, a first longitudinal direction XX′ directed from right to left and a second longitudinal direction XX″, opposite to the first longitudinal direction XX′, i.e. directed from left to right, are defined with reference to the plane of the foil on which
The method according to the invention firstly comprises a step wherein a stack I of alternating foils is produced, these foils being referred to hereinbelow as “anode foils” or “cathode foils” depending on the case at hand. As will be seen in more detail hereafter, each anode foil is intended to form the anode of a plurality of batteries, and each cathode foil is intended to form the cathode of a plurality of batteries. The example in
In one advantageous embodiment, each of these foils has perforations 7 at the four ends thereof so that when these perforations 7 are superimposed, all of the cathodes and all of the anodes of these foils are arranged according to the invention, as will be explained in more detail hereinbelow (see
Each anode foil comprises an anode current-collecting substrate 10 coated at least in part with an active layer 20 of an anode material, hereinafter referred to as an anode layer 20. Each cathode foil comprises a cathode current-collecting substrate 40 coated at least in part with an active layer 50 of a cathode material, hereinafter referred to as a cathode layer 50. Each of these active layers can be solid, and more particularly have a dense or porous nature. Moreover, in order to prevent any electrical contact between two active layers of opposite polarity, an electrolyte layer 30 or a layer of a separator 31 subsequently impregnated with an electrolyte is disposed on the active layer of at least one of these current-collecting substrates previously coated with the active layer, in contact with the opposite active layer. The electrolyte layer 30 or the separator layer 31 can be disposed on the anode layer 20 and/or on the cathode layer 50; the electrolyte layer 30 or the separator layer 31 forms an integral part of the anode foil and/or of the cathode foil comprising same.
Advantageously, the two faces of the anode 10 or respectively cathode 40 current-collecting substrate are coated at least in part with an anode layer 20 or respectively with a cathode layer 50, and optionally with an electrolyte layer 30 or with a separator layer 31, disposed on the anode layer 20 or respectively on the cathode layer 50. In such a case, the anode 10 or respectively the cathode 40 current-collecting substrate acts as a current collector for two adjacent unit cells 100, 100′. The use of these substrates in the batteries increases the production output for rechargeable batteries with a high energy density and a high power density.
The mechanical structure of one of the anode foils is described hereinbelow, wherein the other anode foils have an identical structure. Furthermore, as will be seen hereinbelow, the cathode foils have a structure that is similar to that of the anode foils.
As shown in
The unit entities 60, 60′ are distributed into lines L1 to Ly, disposed one below the other, and into rows R1 to Rx disposed next to one another. By way of non-limiting examples, within the scope of the manufacture of micro-batteries of the surface-mount device type (hereinafter referred to as SMD), the anode and cathode foils used can be 100 mm×100 mm wafers. Typically, the number of lines of these foils is comprised between 10 and 500, whereas the number of rows is comprised between 10 and 500. As a function of the desired battery capacity, the dimensions thereof can vary and the number of lines and rows per anode and cathode foil can be adjusted accordingly. The dimensions of the anode and cathode foils used can be modulated according to requirements. As shown in
The unit entities 60, 60′, 60″ comprise exclusion areas, i.e. uncoated zones 72, 82, coated zones 71, 81, and grooves 70, 80 as will be described in more detail hereinbelow. These grooves 70, 80, which are preferably I-shaped, are penetrating, i.e. they open out respectively on the top and bottom opposing faces of the foil. These grooves 70, 80 are preferably quadrilateral in shape, substantially of the rectangular type. These grooves 70, 80 can be produced in a manner known per se, directly on the current-collecting substrate, prior to any deposition of anode or cathode materials by chemical etching, by electroforming, by laser cutting, by microperforation or by stamping. These grooves 70, 80 can also be made: (i) on current-collecting substrates at least partially coated with a layer of anode or cathode materials, or (ii) on current-collecting substrates at least partially coated with a layer of anode or cathode materials, itself coated with an electrolyte layer or with a separator layer, i.e. on anode or cathode foils.
When the grooves 70, 80 are made in such at least partially coated substrates, the grooves 70, 80 can be made in a manner known per se, for example by laser cutting (or laser ablation), by femtosecond laser cutting, by microperforation or by stamping. The grooves 70, made in all of the cathode foils, are superimposed on top of one another. The grooves 80, made in all of the anode foils, are superimposed on top of one another.
One of the unit entities 60 as shown in
The anode exclusion areas 82 are zones that are free of any electrolyte material or separator and free of any anode material. When produced on the anode foils, these anode exclusion areas 82 are created in such a way as to remove or prevent the deposition of any electrolyte material or separator, of any anode material, and to leave at least part of the anode current-collecting substrate 10. As a result, in a first longitudinal direction XX′ of the battery, each anode current-collecting substrate 10 protrudes from each anode layer 20, and from each layer of electrolyte material 30 or layer of a separator impregnated with an electrolyte 31. When the current-collecting substrates are completely covered with an anode layer 20, itself 20 optionally covered with an electrolyte layer 30 or with a separator layer 31, the anode exclusion areas 82 can be produced by laser ablation in order to locally remove the anode layer 20 or the anode layer 20 coated with an electrolyte layer 30 or with a separator layer 31. The anode exclusion areas 82 can also be produced, in a manner known per se, by local slot-die coating of the current-collecting substrate.
The local slot-die coating of the current-collecting substrate allows for local deposition, on the substrate, in particular of an anode layer 20, optionally subsequently covered according to the same method with an electrolyte layer 30 or with a separator layer 31. Slot-die coating on the substrate with symmetry in the direction of travel of the substrate allows uncoated zones 82 to be directly left on the substrate; this reduces the number of steps in the method for manufacturing the unit entities on the anode foils.
The exclusion area 82, 72 on the one hand, and the groove 80, 70 of the same unit entity 60, 60′,60″ on the other hand, are symmetrical with one another when viewed from overhead, with respect to the centre line of the unit entities 60, 60′,60″, which is denoted by YH.
Each anode exclusion area 82 is produced in the continuation of each cathode groove 70 and each cathode exclusion area 72 is produced in the continuation of each anode groove 80.
The anode foil obtained after producing grooves 80, coated zones 81 and exclusion areas 82 is hereinafter referred to as an anode foil with unit entities 2e.
The following references are used:
H80 is height of the entire anode groove, which is typically comprised between 0.25 mm and 10 mm;
L80 is the width thereof, which is typically comprised between 0.25 mm and 10 mm;
H82 is the height of each anode exclusion area, which is typically comprised between 0.25 mm and 10 mm;
L82 is the width of each anode exclusion area, which is typically comprised between 0.25 mm and 10 mm.
Similarly, each cathode foil is also provided with different lines and rows of cathode unit entities 60, 60″, provided in equal quantities to the anode unit entities 60, 60′.
As shown in particular in
An exclusion area or uncoated zone 72 of a cathode unit entity 60″ is understood to mean the zone of the cathode foil 5e that is not covered by a cathode layer 50 or that is not covered by a cathode layer 50 and an electrolyte layer 30 or a separator layer 31.
A coated zone 81 of a cathode unit entity 60″ is understood to mean the zone of the cathode foil 5e that is covered by a cathode layer 50 or that is covered by a cathode layer 50 and by an electrolyte layer 30 or a separator layer 31. The dimensions of the cathode exclusion areas 72 are identical to those of the anode grooves 80 and, similarly, the dimensions of the anode exclusion areas 82 are similar to those of the cathode grooves 70. When viewed from overhead, the cathode exclusion areas 72 are superimposed on top of the anode grooves 80 and the anode exclusion areas 82 are superimposed on top of the cathode grooves 70.
The only differences between the anode 60′ and cathode 60″ unit entities are that, on the one hand, the cathode exclusion areas 72 and the anode exclusion areas 82 are inverted relative to one another. On the other hand, the cathode grooves 70 and the anode grooves 80 are inverted relative to one another. In this manner, when viewed from overhead, each anode exclusion area 82 is produced in the continuation of each cathode groove 70 and each cathode exclusion area 72 is produced in the continuation of each anode groove 80.
The cathode exclusion areas 72 are zones that are free of any electrolyte material or separator and free of any cathode material. When produced on the cathode foils, these cathode exclusion areas 72 are created in such a way as to remove or prevent the deposition of any electrolyte material or separator, of any cathode material, and to leave at least part of the anode current-collecting substrate 10. In this manner, in the second longitudinal direction XX″ of the battery, opposite the first longitudinal direction XX′, each cathode current-collecting substrate 40 protrudes from each cathode layer 50, and from each layer of electrolyte material 30 or layer of a separator impregnated with an electrolyte 31. When the current-collecting substrates are completely covered with a cathode layer 50, itself 50 optionally covered with an electrolyte layer 30 or with a separator layer 31, the cathode exclusion areas 72 can be produced by laser ablation in order to locally remove the cathode layer 50 or the cathode layer 50 coated with an electrolyte layer 30 or with a separator layer 31. The cathode exclusion areas 72 can also be produced by local slot-die coating of the current-collecting substrate. The local slot-die coating of the current-collecting substrate allows for local deposition, on the substrate, in particular of a cathode layer 50, optionally subsequently covered according to the same method with an electrolyte layer 30 or with a separator layer 31. Slot-die coating on the substrate with symmetry in the direction of travel of the substrate allows uncoated zones 72 to be directly left on the substrate; this reduces the number of steps in the method for manufacturing the unit entities on the cathode foils.
The cathode foil obtained after producing grooves 70, coated zones 71 and exclusion areas 72 is hereinafter referred to as a cathode foil with unit entities 5e.
A stack I alternating at least one anode foil with unit entities 2e and at least one cathode foil with unit entities 5e is then produced so as to obtain at least one unit cell, each unit cell successively comprising an anode current-collecting substrate 10, an anode layer 20, a layer of an electrolyte material 30 or a layer of a separator impregnated or subsequently impregnated with an electrolyte 31, a cathode layer 50, and a cathode current-collecting substrate 40.
The stack I comprises an alternating arrangement of at least one anode foil 2e having grooves 80, uncoated zones 82 and coated zones 81 and of at least one cathode foil 5e having grooves 70, uncoated zones 72 and coated zones 71. At least one unit cell 100 is thus obtained, successively comprising an anode current-collecting substrate 10, an anode layer 20, a layer of an electrolyte material 30 and/or a separator layer 31, a cathode layer 50, and a cathode current-collecting substrate 40.
This stack I is produced such that:
In the case where said battery comprises a plurality of unit cells 100, 100′, 100″, said unit cells 100, 100′, 100″ are disposed one below the other, i.e. superimposed according to a frontal orientation ZZ relative to the main plane of the battery as shown in
It is assumed that the stack, described hereinabove, is subjected to steps ensuring the overall mechanical stability thereof. These steps, which are known per se, in particular include hot pressing the different layers. As will be seen hereinbelow, this stack, consolidated in this manner, allows for the formation of individual batteries, the number whereof is equal to the product of the number of lines Y and the number of rows X.
For this purpose, with reference to
As shown in particular in
Referring back to
In this
Under these conditions, with reference to this
The anode foil with unit entities 2e comprises an anode current-collecting substrate 10 coated with an anode layer 20, itself optionally coated with an electrolyte layer 30 or with a layer of a separator 31 subsequently impregnated with an electrolyte. Each cathode foil with unit entities 5e comprises a cathode current-collecting substrate 40 coated with an active layer of a cathode material 50, itself optionally coated with an electrolyte layer 30 or with a layer of a separator 31 subsequently impregnated with an electrolyte. In order to prevent any electrical contact between two active layers of opposite polarity, i.e. between the anode layer 20 and the cathode layer 50, at least one electrolyte layer 30 and/or at least one layer of a separator 31 impregnated or subsequently impregnated with an electrolyte is/are disposed.
Advantageously, the anode current-collecting substrate 10 of a unit cell 100′ can be adjoined to the anode current-collecting substrate 10 of the adjacent unit cell 100″. Similarly, the cathode current-collecting substrate 40 of a unit cell 100 can be adjoined to the cathode current-collecting substrate 40 of the adjacent unit cell 100′.
In one advantageous embodiment, the anode current-collecting substrate 10, respectively cathode current-collecting substrate 40, can serve as a current collector for two adjacent unit cells, as shown in particular in
As shown in
In the first longitudinal direction XX′, each anode current-collecting substrate 10 protrudes from a first end plane DYa, this first plane being defined by the first longitudinal ends of each anode layer 20, of each layer of electrolyte material 30 or separator layer 31, of each cathode layer 50 and of each cathode current-collecting substrate layer 40.
In the second longitudinal direction XX″ of the battery that is opposite to said first longitudinal direction XX′, each cathode current-collecting substrate 40 protrudes from each anode layer 20, from each layer of electrolyte material 30 or layer of a separator 31 impregnated or subsequently impregnated with an electrolyte, from each cathode layer 50 and from each anode current-collecting substrate layer 10.
This is a particularly advantageous feature of the invention, since it prevents the presence of short-circuits at the lateral edges of the battery, prevents leakage current, and facilitates the making of electrical contact at the anode 1002 and cathode 1006 connection zones. From a cross-sectional view, the cathode exclusion areas 72 are superimposed on top of the anode grooves 80 and the anode exclusion areas 82 are superimposed on top of the cathode grooves 70.
Advantageously, after producing the stack of the anode foils with unit entities 2e and of the cathode foils with unit entities 5e, the stack I is consolidated by heat and/or mechanical treatment (this treatment can be a thermocompression treatment, comprising the simultaneous application of a pressure and a high temperature). The heat treatment of the stack enabling the battery to be assembled is advantageously carried out at a temperature comprised between 50° C. and 500° C., preferably at a temperature below 350° C. The mechanical compression of the stack of the anode foils with unit entities 2e and of the cathode foils with unit entities 5e to be assembled is carried out at a pressure comprised between 10 MPa and 100 MPa, preferably between 20 MPa and 50 MPa.
The production of the consolidated stack of the layers that make up the battery has just been described. Then, when the stack I comprises a plurality of lines, i.e. at least two lines of unit entities, also referred to hereinafter as battery lines Ln, a first pair of cuts DXn and DX′n can be made to separate a given line Ln of batteries 1000 from at least one other line Ln−1, Ln+1 of batteries formed from said consolidated stack. Each cut, which is made in a penetrating manner, i.e. it extends through the entire height of the stack, is made in a manner known per se, as indicated hereinabove. As shown in
When a separator is used as an electrolyte host matrix, the previously obtained consolidated stack or the line Ln of batteries 1000 can be impregnated when the initial stack I comprises a plurality of lines of batteries Ln and when a first pair of cuts (DXn, DX′n) has been made in order to separate the given line (Ln) of batteries (1000) from at least one other line (Ln−1, Ln+1) of batteries (1000) formed from said consolidated stack. The impregnation of the previously obtained consolidated stack or of the line Ln of batteries 1000 can be produced by a phase carrying lithium ions such as liquid electrolytes or an ionic liquid containing lithium salts, such that said separator (31) is impregnated with an electrolyte.
After producing a consolidated stack I, optionally impregnated with a phase carrying lithium ions, this stack or the line Ln of batteries 1000 is encapsulated by depositing an encapsulation system 95 to ensure the protection of the cell of the battery from the atmosphere, as shown in
For the purposes of the invention, an impervious layer is defined as having a water vapour permeance (WVTR) of less than 10−5 g/m2.d. The water vapour permeance can be measured using a method that is the object of the U.S. Pat. document No. 7,624,621 and that is also described in the publication “Structural properties of ultraviolet cured polysilazane gas barrier layers on polymer substrates” by A. Mortier et al. published in Thin Solid Films 6+550 (2014) 85-89.
Typically, the first cover layer, which is optional, is selected from the group consisting of: silicones (for example deposited by impregnation or by plasma-enhanced chemical vapour deposition from hexamethyldisiloxane (HMDSO)), epoxy resins, polyimide, polyamide, poly-para-xylylene (also called poly(p-xylylene), but better known as parylene), and/or a mixture thereof. When a first cover layer is deposited, it protects the sensitive elements of the battery from the environment thereof. The thickness of said first cover layer is preferably comprised between 0.5 μm and 3 μpm.
This first cover layer is especially useful when the electrolyte and electrode layers of the battery have porosities: it acts as a planarisation layer, which also has a barrier effect. By way of example, this first layer is capable of lining the surface of the microporosities opening out onto the surface of the layer, to close off the access thereto. In this first cover layer, different parylene variants can be used. Parylene C, parylene D, parylene N (CAS 1633-22-3), parylene F or a mixture of parylene C, D, N and/or F can be used. Parylene is a dielectric, transparent, semi-crystalline material with high thermodynamic stability, excellent resistance to solvents and very low permeability. Parylene also has barrier properties. Parylene F is preferred within the scope of the present invention.
This first cover layer is advantageously obtained from the condensation of gaseous monomers deposited by chemical vapour deposition (CVD) on the surfaces of the stack of the battery, which results in a conformal, thin and uniform covering of all of the accessible surfaces of the stack. This first cover layer is advantageously stiff; it cannot be considered to be a flexible surface.
The second cover layer, which is also optional, is formed by an electrically insulating material, preferably an inorganic material. It is deposited by atomic layer deposition (ALD), by PECVD, by HDPCVD (high density plasma chemical vapour deposition) or by ICP CVD (inductively coupled plasma chemical vapour deposition) in order to obtain a conformal covering of all of the accessible surfaces of the stack previously covered with the first cover layer. The layers deposited by ALD are mechanically very fragile and require a stiff bearing surface to fulfil their protective role. The deposition of a fragile layer on a flexible surface would result in the formation of cracks, causing this protective layer to lose integrity. Furthermore, the growth of the layer deposited by ALD is influenced by the nature of the substrate. A layer deposited by ALD on a substrate having zones of different chemical natures will have inhomogeneous growth, which can cause this protective layer to lose integrity. For this reason, this optional second layer, where present, preferably bears against said optional first layer, which ensures a chemically homogeneous growth substrate.
ALD deposition techniques are particularly well suited for covering surfaces with a high roughness in a completely impervious and conformal manner. They allow for the production of conformal layers, free of defects such as holes (so-called “pinhole-free” layers) and represent very good barriers. The WVTR thereof is extremely low. The WVTR (water vapour transmission rate) is used to evaluate the water vapour permeance of the encapsulation system. The lower the WVTR, the more impervious the encapsulation system. The thickness of this second layer is advantageously chosen as a function of the desired level of imperviousness to gases, i.e. the desired WVTR, and depends on the deposition technique used, chosen in particular from among ALD, PECVD, HDPCVD and ICP CVD.
Said second cover layer can be made of a ceramic material, vitreous material or glass-ceramic material, for example in the form of an oxide, of the Al2O3 or Ta2O5 type, a nitride, a phosphate, an oxynitride or a siloxane. This second cover layer preferably has a thickness comprised between 10 nm and 10 μm, preferably between 10 nm and 50 nm.
This second cover layer deposited by ALD, PECVD, HDPCVD (high density plasma chemical vapour deposition) or ICP CVD (inductively coupled plasma chemical vapour deposition) on the first cover layer firstly makes it possible to render the structure impervious, i.e. to prevent water from migrating inside the object, and secondly makes it possible to protect the first cover layer, which is preferably made of parylene F, from the atmosphere, in particular from air and moisture, and from thermal exposure in order to prevent the degradation thereof. This second cover layer thus improves the life of the encapsulated battery.
Said second cover layer can also be deposited directly on the stack of anode and cathode foils, i.e. in the case where said first cover layer has not been deposited.
The third cover layer must be impervious and preferably has a water vapour permeance (WVTR) of less than 10-5 g/m2.d. This third cover layer is formed by a ceramic material and/or a low melting point glass, preferably a glass having a melting point below 600° C., deposited at the outer periphery of the stack of anode and cathode foils or of the first cover layer. The ceramic and/or glass material used in this third layer is advantageously chosen from among:
These glasses can be deposited by moulding or dip coating. The ceramic materials are advantageously deposited by PECVD or preferably by HDPCVD or ICP CVD at a low temperature; these methods allow a layer with good imperviousness to be deposited.
As described hereinabove, the battery according to the invention comprises an encapsulation system which, advantageously, is produced in the form of a succession of layers. This procures a highly impervious encapsulation on all of the faces of the battery. Moreover, this encapsulation has very small overall dimensions, which allows for the miniaturisation required to produce microbatteries.
The above description of the encapsulation system illustrates a significant difference, together with its technical effects, when compared to the disclosure of the U.S. patent document U.S. Patent Publication No. 2018/0212210 filed by Suzuki. In this battery of the prior art, the resin in contact with the cells does not fulfil an impervious encapsulation function. More specifically, this resin does not have the permeance features described hereinabove.
Furthermore, this document filed by Suzuki relates to a solid-state battery. Conversely, the battery according to the invention can be not fully solid. In such a case, the longitudinal ends of this battery are of the “open” type. As shown in particular in
Furthermore, the encapsulation system of the battery according to the invention is advantageously electrically insulating. For the purpose of the invention, thus means that the conductivity of this encapsulation system is advantageously less than 10e-11 S.m−1, in particular less than 10e-12 S.m−1. Such a feature is advantageous since it avoids short circuits, while at the same time allowing the opposite positive and negative connections to be reworked for compatibility with a pick-and-place type electronic component placement machine. This feature can be compared with the disclosure of the aforementioned patent document filed by Suzuki, wherein the imperviousness is provided by an outer casing of a metallic nature.
The stack thus coated is then cut by any suitable means along the cutting lines DYn and DY′n, so as to expose the anode 1002 and cathode 1006 connection zones and obtain unit batteries as shown in
As shown in
only each cathode edge 1006′ of each cathode current-collecting substrate 40 protrudes from the second end plane (DY′a), this second plane being defined by the second longitudinal ends of each anode layer 20, of each layer of electrolyte material 30 and/or separator layer 31, of each cathode layer 50 and of each anode current-collecting substrate layer 10 in the second longitudinal direction XX″ of the battery, and lies flush with a second longitudinal face F4, said second longitudinal face F4 preferably being opposite and parallel to the first longitudinal face F6, wherein each anode edge 1002′ defines an anode connection zone 1002 and each cathode edge 1006′ defines a cathode connection zone 1006.
Contact members 97, 97′, 97″ (electrical contacts) are added where the cathode 1006 or respectively anode 1002 connection zones are apparent. These contact zones are preferably disposed on opposite sides of the stack of the battery to collect the current (lateral current collectors). The contact members 97, 97′, 97″ are disposed at least on the cathode connection zone 1006 and at least on the anode connection zone 1002, preferably on the face of the coated and cut stack comprising at least the cathode connection zone 1006 and on the face of the coated and cut stack comprising at least the anode connection zone 1002 (see
Thus, at least the anode connection zone 1002, preferably at least the first longitudinal face F6 comprising at least the anode connection zone 1002, and more preferably the first longitudinal face F6 comprising at least the anode connection zone 1002, and the ends 97′a of the faces F1, F2, F3, F5 adjacent to this first longitudinal face F6, are covered by an anode contact member 97′, capable of producing the electrical contact between the stack I and an external conductive element. Furthermore, at least the cathode connection zone 1006, preferably at least the second longitudinal face F4 comprising at least the cathode connection zone 1006, and more preferably the second longitudinal face F4 comprising at least the cathode connection zone 1006, and the ends 97″a of the faces F1, F2, F3, F5 adjacent to this second longitudinal face F4, are covered by a cathode contact member 97″, capable of producing the electrical contact between the stack I and an external conductive element.
Preferably, the contact members 97, 97′, 97″ are constituted, in the vicinity of the cathode 1006 and anode 1002 connection zones, by a stack I of layers successively comprising a first electrical connection layer comprising a material filled with electrically conductive particles, preferably a polymeric resin and/or a material obtained by a sol-gel method, filled with electrically conductive particles and more preferably a graphite-filled polymeric resin, and a second layer consisting of a metal foil disposed on the first layer.
The first electrical connection layer allows the subsequent second electrical connection layer to be fastened while providing “flexibility” at the connection without breaking the electrical contact when the electric circuit is subjected to thermal and/or vibratory stresses.
The second electrical connection layer is a metal foil. This second electrical connection layer is used to provide the batteries with lasting protection against moisture. In general, for a given thickness of material, metals make it possible to produce highly impervious films, more impervious than ceramic-based films and even more impervious than polymer-based films, which are generally not very impervious to the passage of water molecules. It increases the calendar life of the battery by reducing the WVTR at the contact members.
Advantageously, a third electrical connection layer comprising a conductive ink can be deposited on the second electrical connection layer; the purpose thereof is to reduce the WVTR, thus increasing the life of the battery.
The contact members 97, 97′, 97″ allow the electrical connections to be made alternating between positive and negative at each of the ends. These contact members 97, 97′, 97″ enable parallel electrical connections to be made between the different battery elements. For this purpose, only the cathode connections protrude at one end, and the anode connections are available at another end.
International Patent Publication No. WO 2016/001584 describes stacks of a plurality of unit cells, made up of anode and cathode foils stacked in an alternating manner and laterally offset (see
According to the present invention, this risk is eliminated with the use of foils carrying unit entities wherein:
The hot-pressed mechanical structure of unit entities is extremely rigid in the vicinity of the cut, due to the alternating superimposition of cathode and anode foils. The use of such a stiff structure, together with the use of foils bearing unit entities, allows the number of defects during cutting to be reduced, the cutting speed to be increased and thus the production output of the batteries to be improved.
According to the invention, the cuts DY′n and DYn are made through the anode foils with unit entities 2e and the cathode foils with unit entities 5e of similar density, resulting in a higher quality, clean cut. Furthermore, in the vicinity of the cutting planes DY′n and DYn, the presence, in the first longitudinal direction XX′, of an anode current-collecting collecting substrate 10 free of any anode material, electrolyte, separator impregnated or not impregnated with an electrolyte, cathode and cathode current-collecting substrate, as well as the presence, in the second longitudinal direction XX″, of a cathode current-collecting substrate 40 free of any anode material, electrolyte, separator impregnated or not impregnated with an electrolyte, cathode and anode current-collecting substrate, prevents any risk of a short-circuit and leakage current, and facilitates the making of electrical contact at the connection zones 1002, 1006. The anode connection zones 1002 and the cathode connection zones 1006 are preferably laterally opposite one another.
The unique structure of the battery according to the invention prevents the presence of short-circuits at the longitudinal faces F4, F6 of the battery, prevents leakage current, and facilitates the making of electrical contact at the anode 1002 and cathode 1006 connection zones. More specifically, the absence of electrode materials and of electrolyte materials on the longitudinal faces F4, F6 of the battery comprising the anode and cathode connection zones, prevents the lateral leakage of lithium ions and facilitates the balancing of the battery; the effective surfaces of the electrodes in contact with one another, and delimited by the first and second end planes DYa, DY′a are substantially identical as shown in
In the alternative, and as shown in
The batteries according to the invention can be made from unit entities according to different alternative embodiments of the invention. In a non-limiting example, as shown in
As shown in
In an alternative embodiment not shown, the exclusion areas of each unit entity of a row Rn can be produced from an exclusion strip that is common to each unit entity of the same row Rn, thus optimising the production output of the batteries while preventing the presence of material offcuts 90. The central part 4 of the stack of alternating foils is thus used in full to manufacture batteries according to the invention.
With reference to this
Cuts are then made, along the vertical lines 392 and 393 shown in this FIG. 19. As shown in
The battery 1400 in this
In a similar manner to the battery 1300, the battery 1500 shown in
However, the battery 1500 differs from that 1300, firstly in that the current-collecting substrates 510 and 540 do not protrude in the longitudinal orientation XX from the other layers. Moreover, this battery 1500 is equipped with two additional components, i.e. electrical connection members 560 and 570, which are provided on the opposite end faces of the cell 600. Each of these connection members, which are in particular identical to one another, typically has a thickness of less than 300 μm, preferably less than 100 μm.
Each connection member is advantageously made of an electrically conductive material, in particular a metal material. This in particular includes aluminium, copper or a stainless steel. In order to improve the weldability thereof, these materials can be coated with a thin layer of gold, nickel or tin.
The means of attachment between, on the one hand, the connection member 560 and the current collector 510 and, on the other hand, the connection member 570 and the current collector 540 will now be described. These means of attachment are typically formed by a conductive adhesive, in particular a graphite adhesive, or an adhesive charged with copper or aluminium metal nanoparticles. This conductive adhesive layer, which is not shown in
As shown in
The cell 600, equipped with the connection members, is then covered with the encapsulation system. As shown in
There are specific advantages to the embodiments shown in
Finally, the embodiments shown in
With reference to these embodiments in
The battery being characterised in that it further comprises two electrical connection members 560, 570, provided on the opposite end faces of the stack, a first end 562, 572 of each electrical connection member protruding, in the longitudinal orientation XX, beyond a respective longitudinal face F4, F6 of the stack.
According to other features of this battery according to this additional object of the invention: (i) the first end 562 of a connection member 560 protrudes in a first direction, beyond a first longitudinal face F4, whereas the first end 572 of the other connection member 570 protrudes, in the opposite direction, from the other longitudinal face F6, (ii) the first end 662, 672 of the two connection members 660, 670 protrudes in the same direction, beyond one and the same longitudinal face F4, (iii) each electrical connection member is attached to a respective current-collecting substrate, in particular by means of a conductive adhesive, (iv) none of the current-collecting substrates, as well as the anode, cathode and separator layers, protrude beyond the longitudinal faces of the stack, and opposite the protruding end, each electrical connection member delimits a shoulder 564, 574 with said stack.
The method according to the invention is particularly adapted to the manufacture of all-solid-state batteries, i.e. batteries whose electrodes and electrolyte are solid and do not comprise a liquid phase, even impregnated in the solid phase. The method according to the invention is particularly adapted to the manufacture of batteries considered to be quasi-solid-state comprising at least one separator 31 impregnated with an electrolyte. The separator is preferably a porous inorganic layer having: (i) a porosity, preferably mesoporous, that is greater than 30%, preferably comprised between 35% and 50%, and more preferably between 40% and 50%, and (ii) pores with an average diameter D50 of less than 50 nm.
The thickness of the separator is advantageously less than 10 pm, preferably comprised between 2.5 μm and 4.5 μm, so as to reduce the final thickness of the battery without weakening the properties thereof. The pores of the separator are impregnated with an electrolyte, preferably with a phase carrying lithium ions such as liquid electrolytes or an ionic liquid containing lithium salts. The “nano-confined” or “nano-entrapped” liquid in the porosities, and in particular in the mesoporosities, can no longer escape. It is bound by a phenomenon referred to herein as “absorption in the mesoporous structure” (which does not seem to have been described in the literature within the context of lithium-ion batteries) and it can no longer escape, even when the cell is placed in a vacuum. The battery is thus considered to be a quasi-solid-state battery.
The battery according to the invention can be a lithium-ion microbattery, a lithium-ion mini-battery, or a high-power lithium-ion battery. In particular, it can be designed and dimensioned to have a capacity of less than or equal to about 1 mA h (commonly known as a “microbattery”), to have a power of greater than about 1 mA h up to about 1 A h (commonly known as a “mini-battery”), or to have a capacity of greater than about 1 A h (commonly known as a “high-power battery”). Typically, microbatteries are designed to be compatible with methods for manufacturing microelectronics.
The batteries of each of these three power ranges can be produced: (i) with layers of the “solid-state” type, i.e. without impregnated liquid or paste phases (said liquid or paste phases can be a lithium-ion conductive medium, capable of acting as an electrolyte), or (ii) with layers of the mesoporous “solid-state” type, impregnated with a liquid or paste phase, typically a lithium-ion conductive medium, which spontaneously penetrates the layer and no longer emerges therefrom, so that the layer can be considered to be quasi-solid, or (iii) with impregnated porous layers (i.e. layers with a network of open pores which can be impregnated with a liquid or paste phase, which gives these layers wet properties).
The following references are used in these figures and in the description hereinbelow:
1000, 1000′ Battery according to the invention
1002 Anode connection zone
1002′ Anode edge of each anode current-collecting substrate
1006 Cathode connection zone
1006′ Cathode edge of each cathode current-collecting substrate
100, 100′, 100″ Unit cell
10 Anode current-collecting substrate
20 Anode layer
30 Layer of an electrolyte material/Electrolyte layer
31 Layer of a separator impregnated or subsequently impregnated with an electrolyte/Separator layer
40 Cathode current-collecting substrate
50 Cathode layer
60 Unit entity
60′ Anode unit entity
60″ Cathode unit entity
70 I-shaped grooves in the cathode foils, cathode groove
H70 Overall height of the I-shaped cathode groove 70
L70 Overall width of the I-shaped cathode groove 70
71 Coated zone in the cathode foil
72 Exclusion area/Uncoated zone in the cathode foil/Cathode exclusion area
L72 Overall width of the exclusion area/uncoated zone 72 in the cathode foil
H72 Overall height of the exclusion area/uncoated zone 72 in the cathode foil
L71 Overall width of the coated zone in the cathode foil
80 I-shaped grooves in the anode foils, anode groove
H80 Overall height of the I-shaped anode groove 80
L80 Overall width of the I-shaped anode groove 80
81 Coated zone in the anode foil
82 Exclusion area/Uncoated zone in the anode foil/Anode exclusion area
82′ Exclusion strip
L81 Overall width of the coated zone in the anode foil
H81 Overall height of the coated zone in the anode foil
L82 Overall width of the exclusion area/uncoated zone 82
H82 Overall height of the exclusion area/uncoated zone 82
90 Material offcuts
95 Encapsulation system
97 Contact member
97′ Anode contact member
97′a Anode contact member pin covering the ends of the faces F1, F2, F3, F5 adjacent to the longitudinal face F6
97″ Cathode contact member
97″a Cathode contact member pin covering the ends of the faces F1, F2, F3, F5 adjacent to the longitudinal face F4
Dca The smallest distance between the first longitudinal face F6 of a battery 1000 comprising at least one anode connection zone 1002 and the first end plane DYa
Dcc The smallest distance between the second longitudinal face F4 of a battery 1000 comprising at least one cathode connection zone 1006 and the second end plane DY′a
Dca′ The smallest distance between the first longitudinal face of a battery 1000′ comprising at least one anode connection zone and the first end plane defined by the first longitudinal ends of each anode layer, of each layer of electrolyte material or separator layer, of each cathode layer and of each cathode current-collecting substrate layer
Dcc′ The smallest distance between the second longitudinal face of a battery 1000′ comprising at least one cathode connection zone and the second end plane defined by the first longitudinal ends of each anode layer, of each layer of electrolyte material or separator layer, of each cathode layer and of each anode current-collecting substrate layer
I1000 Width of the battery
L1000 Length of the battery
C1000 Centre of the battery 1000
Z1000 Axis parallel to the frontal orientation ZZ of the battery and passing through the centre C1000 of the battery 1000.
R1000 Rotation of the battery 1000 about Z1000
I Stack of substrate foils, covered with an electrode layer (anode or cathode) and with an electrolyte foil or with a foil of a separator impregnated or subsequently impregnated with an electrolyte/Stack of at least one unit cell
2
e Anode foil with unit entities
5
e Cathode foil with unit entities
4 Perforated central zone of the anode foil with unit entities
6 Peripheral frame of the anode foil with unit entities
7 Perforations present at the four ends of the foils of substrate, anode, cathode, electrolyte or separator impregnated or subsequently impregnated with an electrolyte
8 Material bridges between two lines
H8 Height of the bridges
9 Material strips between two rows
L9 Width of the strips
XX Longitudinal or horizontal orientation of the stack/of the battery
YY Lateral or transverse orientation of the stack/of the battery
ZZ Frontal orientation of the stack/of the battery
L, Ln, Ln−1, Ln+1 Line of the unit entities/battery line
R, Rn, Rn−1, Rn+1 Row of the unit entities
DYn−1, DY′n−1, DYn, DY′n, DYn+1, DY′n+1 Cuts
DXn−1, DX′n−1, DXn, DX′n, DXn+1, DX′n+1 Cuts
DYa First end plane of a battery defined by the first longitudinal ends of each anode layer, of each layer of electrolyte material or separator layer, of each cathode layer and of each cathode current-collecting substrate layer.
DY′a Second end plane of a battery defined by the second longitudinal ends of each anode layer, of each layer of electrolyte material or separator layer, of each cathode layer and of each anode current-collecting substrate layer.
2000 Battery according to the prior art
200, 200′, 200″ Unit cell of a battery according to the prior art
2002 Anode connection zone of a battery according to the prior art
2006 Cathode connection zone of a battery according to the prior art
295 System for encapsulating a battery according to the prior art
YH Lateral centre line of the unit entities
F1, F2 End faces of the stack I/of the battery 1000
F3, F5 Lateral faces of the stack I/of the battery 1000
F4, F6 Longitudinal faces of the stack I/of the battery 1000
FF1, FF2 End faces of the battery line Ln
FF3, FF5 Lateral faces of the battery line Ln
FF4, FF6 Lateral faces of the battery line Ln
| Number | Date | Country | Kind |
|---|---|---|---|
| 20166569.2 | Mar 2020 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2021/052375 | 3/23/2021 | WO |
